Apparatus for positioning of a medical device in body tissue includes an angle indexer which mates in at least two positions with an index-key attached to the medical device. The indexer may be hand held or otherwise secured to a separate device, such as an introducer cannula, with the medical device being rotatable relative to the indexer.
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1. A probe assembly, comprising:
a cannula having a shaft and a lumen extending within the cannula shaft;
a medical probe configured for being introduced into a proximal end of the cannula shaft and advanced within the cannula lumen, the medical probe having a shaft and at least one deployable medical operative element disposed on a distal end of the probe shaft for being positioned in body tissue;
an index-key coupled to the medical probe; and
an indexer coupled to the cannula and adapted to mate with the index-key in at least two rotational positions, such that each of the at least one medical operative element can be deployed in at least two different radial directions relative to a longitudinal axis of the cannula.
21. A probe assembly, comprising:
a cannula having a shaft and a lumen extending within the cannula shaft;
a medical probe configured for being introduced into a proximal end of the cannula shaft and advanced within the cannula lumen, the medical probe having a shaft and at least one ablation element disposed on a distal end of the probe shaft for creating an ablation pattern within body tissue;
an index-key coupled to the medical probe; and
an indexer coupled to the cannula and adapted to mate with the index-key in at least two rotational positions, such that the ablation pattern has one rotational orientation when the indexer is mated with the index-key in a first one of the at least two rotational positions, and the ablation pattern has another different rotational orientation when the indexer is mated with the index-key in a second one of the at least two rotational positions.
2. The probe assembly of
3. The probe assembly of
6. The probe assembly of
7. The probe assembly of
8. The probe assembly of
9. The probe assembly of
12. The probe assembly of
13. The probe assembly of
14. The probe assembly of
15. The probe assembly of
16. A method of performing a medical procedure using the probe assembly of
positioning the cannula in a target tissue region;
introducing the medical probe into the proximal end of the cannula;
advancing the medical probe within the cannula, so that a distal end of the medical probe is positioned proximate the target tissue region;
mating the index-key and indexer in a first one of the at least two rotational positions;
deploying the at least one medical operative element in a first one of the at least two different radial directions when the index-key and indexer is in the first rotational position;
operating the medical probe to perform a medical function on the target tissue region, while the index-key and indexer are mated in the first rotational position;
withdrawing the medical probe within the cannula;
mating the index-key and indexer in a second one of the at least two rotational positions;
deploying the at least one medical operative element in a second one of the at least two different radial directions when the index-key and indexer is in the second rotational position; and
operating the medical probe to perform another medical function on the target tissue region.
17. The method of
18. The method of
19. The method of
20. The method of
22. The probe assembly of
23. The probe assembly of
26. The probe assembly of
27. The probe assembly of
28. The probe assembly of
31. The probe assembly of
32. The probe assembly of
33. The probe assembly of
34. The probe assembly of
35. The probe assembly of
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This application is a continuation-in-part of U.S. patent application Ser. No. 10/317,796, now U.S. Pat. No. 6,926,713 filed Dec. 11, 2002, the disclosure of which is fully incorporated by reference herein.
The invention relates generally to medical devices, and more particularly, to systems for positioning medical probes in organs or cavities.
Radio frequency ablation (RFA) involves the destruction of undesirable cells by generating heat through agitation caused by the application of alternating electrical current (radio frequency energy) through tissue. Various RFA ablation devices have been designed to perform this treatment. For example, U.S. Pat. No. 5,855,576 describes an ablation apparatus that includes an array of wire electrodes that are deployed through a catheter. Proximal ends of the wires are connected to a RF power source (generator), with the distal ends projecting generally radially and uniformly spaced apart into a target tissue structure (e.g., a tumor) from the catheter distal end. The wire ends act as electrodes that may be energized in a monopolar or bipolar fashion to heat and necrose tissue within a defined volumetric region of target tissue. The current can flow between closely spaced energized wire electrodes or between an energized wire electrode and a larger, common electrode located remotely from the tissue to be heated. In order to assure that the target tissue is adequately treated and limit damage to adjacent healthy tissues, it is desirable that the array formed by the wires within the tissue be precisely and uniformly defined. In particular, it is generally desirable that the independent wires be evenly and symmetrically spaced-apart so that heat is generated uniformly within the desired target tissue volume. The ablation device may be used either in an open surgical setting, in laparoscopic (small incision) procedures, or in percutaneous (through the skin) interventions.
For example,
Due to physical changes within the tissue during the ablation process, the desired thermal lesion 6 illustrated in
In accordance with a general aspect, the invention provides an angle indexing apparatus for positioning a medical device in a plurality of radial orientations. While embodiments of the invention are useful for overcoming the above-described difficulties regarding the placement and repositioning of RFA devices in a target tissue site, the invention is not so limited, but is more generally directed to placement and orientation of any medical device in body tissue.
In one embodiment, the apparatus includes an index-key configured for coupling to a medical device, and an indexer securable in a position relative to which the index-key may be rotated, wherein the index-key is adapted to mate with the indexer in at least two positions. By way of non-limiting examples, one of the indexer and index-key may have at least two keyways, with the other of the indexer and index-key having at least one key element adapted to mate with each of the at least two keyways. In one embodiment, the at least two keyways lie along two radial lines that define one or more angles equal to or less than 90°.
In embodiments of the invention, the index-key may be adapted to fit within the indexer, or vice versa. The indexer may be configured for coupling to an introducer through which the medical device is positioned in tissue. Alternately and/or additionally, the indexer may be adapted to be hand-held by an operator.
Embodiments of the invention are well-suited for certain medical devices, such as energy delivery probe having an array of spaced electrodes for performing RFA procedures in body tissue. In one such embodiment, the medical device is a RFA probe having at least two spaced electrodes that are placed in a first orientation when the index key is mated with the indexer in a first position, and in a second orientation when the index key is mated with the indexer in a second position.
In another embodiment, the medical device may be an imaging probe, a sensing (e.g., temperature) probe, or any other probe that may be selectively placed in a relative radial orientation in body tissue using the respective indexer and index-key.
In accordance with still another embodiment of the invention, a method for delivering energy to a target tissue region in a body, includes positioning an introducer in the target tissue region, the introducer having a lumen and a distal end opening, the introducer further having an indexer coupled to a proximal portion thereof; positioning an energy delivery probe through the introducer lumen so that a distal end of the energy delivery probe is positioned proximate the distal end opening of the introducer in the target tissue region, the energy delivery probe having an index-key coupled to a proximal portion thereof, the index-key adapted to mate with the indexer in at least two positions; mating the index-key and indexer in a first position, and deploying an electrode in a first orientation from the distal end of the energy delivery probe into tissue; transmitting energy from the electrode in the first orientation to tissue; withdrawing the electrode from the tissue and into the energy delivery probe; mating the index-key and indexer in a second position, and deploying the electrode in a second orientation from the distal end of the energy delivery probe into tissue; and transmitting energy from the electrode in the second orientation to tissue.
In accordance with yet another embodiment of the invention, a method of measuring temperature of a target tissue region in a body, includes positioning an introducer in the target tissue region, the introducer having a lumen and a distal end opening, the introducer further having an indexer coupled to a proximal portion thereof; positioning a temperature sensing probe through the introducer lumen so that a distal end of the temperature sensing probe is positioned proximate the distal end opening of the introducer in the target tissue region, the temperature sensing probe having an index-key coupled to a proximal portion thereof, the index-key adapted to mate with the indexer in at least two positions; mating the index-key and indexer in a first position and deploying the distal end of the temperature sensing probe in a first orientation from the introducer lumen into tissue; sensing a tissue temperature with the probe distal end in the first orientation; withdrawing the probe distal end from the tissue and into the introducer lumen; mating the index-key and indexer in a second position, and deploying the distal end of the temperature sensing probe in a second orientation from the introducer lumen into tissue; and sensing a tissue temperature with the probe distal end in the second orientation.
Other aspects and features of the invention will be evident from reading the following detailed description of the embodiments, which are intended to illustrate, and not limit, the invention.
The drawings illustrate the design and utility of embodiments of the invention, in which similar elements are referred to by common reference numerals, and in which:
Various embodiments of the invention are described hereinafter with reference to the figures. It should be noted that the figures are not drawn to scale and that elements of similar figures structures or functions are represented by like reference numerals throughout the figures. It should also be noted that the figures are only intended to facilitate the description of specific embodiments and are not intended as an exhaustive description or as a limitation on the scope of the invention. Aspects, features, and advantages described in conjunction with a particular embodiment are not necessarily limited to that embodiment and may be practiced with other embodiments of the invention, even if not so illustrated or specifically described. Similarly, while the disclosed embodiments are primarily energy delivery probes, such as RFA probes, the invention is not so limited to such devices or uses, and may be employed for other device types and uses, such as biopsy or temperature probes.
Referring to
The cannula 12 may be made of a variety of materials, including, but not limited to, plastics, metals, and polymers. Preferably, the cannula 12 is rigid, i.e., by being made of a stiff material, or by being reinforced with a coating or coil, to provide axial strength. The outer diameter of the cannula 12 is preferably less than ½ inch. However, other dimensions for the outer diameter of the cannula 12 may also be appropriate, depending on the particular application or clinical procedure. The cannula 12 should have an inner diameter that allows the shaft 14 to be inserted and slid within the lumen 26 of the cannula 12.
The shaft 14 is preferably rigid and is composed of a metal. However, the shaft 14 may also be made of other materials, including, but not limited to plastics, nitinol, titanium, methacrylates, and alloys. The shaft 14 preferably has a circular cross section. Alternatively, the shaft 14 may have other cross sectional shapes, such as square, rectangle, or customized shapes.
In the embodiment shown in
As shown in
The indexer 22a is preferably made of plastic or polymer, but can also be made of other materials, such as metals. The indexer 22a is preferably separately manufactured from the cannula 12, and is then subsequently detachably coupled to the proximal end of the cannula 12. For such purpose, a luer-type connection may be used as the securing mechanism between the indexer 22 and the proximal end of the cannula 12. Alternatively, the securing mechanism may be a friction-type connection, or a screw-type connection, as are commonly known to those skilled in the art. The indexer 22a may also be permanently secured to the proximal end of the cannula 12 by welding, brazing, glue, or other types of adhesive, depending on the materials from which the indexer 22a and the cannula 12 are made. Still another alternative is to fabricate, the indexer 22a together with the cannula 12 as one single component.
The index-key 24a is secured to the shaft 14 and includes a single key element 25 (shown in
Referring further to
The indexer 22a includes two keyways 34a and 34b located on the interior surface 35 of the indexer 22a. The keyways 34a and 34b are located along respective radial lines 36a and 36b, which form an angle 37 therebetween. The index-key 24a is adapted to mate with the indexer 22a, such that when the shaft 14 is inserted into the lumen 26 of the cannula 12, the key element 25 of the index-key 24a fits within one of the keyways 34a and 34b of the indexer 22a. Particularly, when the key element 25 of the index-key 24a fits within the keyway 34a of the indexer 22a, the shaft 14 is guided to slide within the lumen 26 of the cannula 12 in a first rotational orientation. When the key element 25 of the index-key 24a fits within the keyway 34b of the indexer 22a, the shaft 14 is guided to slide within the lumen 26 of the cannula 12 in a second rotational orientation that is offset from the first rotational orientation by angle 37. Accordingly, the electrode array carried at the distal end 16 of the shaft 14 can have two operative positions or orientations that correspond with the orientations of the keyways 34a and 34b of the indexer 22a. As will be described in further detail below, the designed magnitude of the angle 37 will depend on the number of wires 21.
The distance through which the index-key 24a longitudinally travels within either of the keyways 34a and 34b of the indexer 22a may vary. In the illustrated embodiment, the indexer 22a has a length 31, such that the shaft 14 is rotationally guided by the indexer 22a until the wires 21 at the distal end 16 of the shaft 14 are completely deployed. Alternatively, the shaft 14 may be rotationally guided by the indexer 22a only during the initial deployment range of the wires 21. In certain clinical situations or procedures, guiding the shaft 14 through the complete deployment range of the wires 21 may not be necessary. For example, once a portion of each of the wires 21 is deployed into a target tissue, the distal end 16 of the shaft 14 becomes rotatably secured, at least to a certain extent, by the tissue. As such, any further advancement of the shaft 14 could be guided by the tissue without the help of the angle indexing apparatus 19.
Although the previously described indexer 22a includes two keyways 34a, 34b, the number of keyways and the angle formed between the keyways may vary, depending on the particular application or clinical procedure.
Having just described the structure of the probe assembly 10, its operation in performing multiple ablations will now be described with reference to
Referring now to
After the cannula 12 is properly placed, the shaft 14 is distally advanced until the index-key 24a is mated with the indexer 22a, thereby guiding the wires 21 to deploy radially outward from the distal end of the cannula 12, as shown in
If the indexer 22a of
In another example, the indexer 22a illustrated in
As shown in
Referring now to
Turning to
The sleeve 52 of the index-key 24b is adapted to coaxially secure the shaft 14 to the index-key 24b. In one embodiment, the diameter of the bore 58 is made sufficiently small so that the sleeve 52 acts as a friction-type connection. Alternatively, the inner surface of the sleeve 52 and the proximal end 18 of the shaft 14 may include screw-threads, and the index-key 24b is then secured to the shaft 14 by screwing the shaft 14 into the threaded sleeve 58 of the index-key 24b. As a further alternative, the bore 58 may have a diameter that is slightly larger than the diameter of the shaft 14, and the index-key 24b is then secured to the shaft 14 by bonding the interior surface of the sleeve 52 to the proximal end 18 of the shaft 14. The optional proximal disk 56 can then be secured to the distal face of the handle 28 by using glue or other appropriate adhesives. It should be noted that regardless of the type of connection used to secure the index-key 24b to the shaft 14, the index-key 24b should be rigidly secured to the shaft 14 so that the index-key 24b cannot coaxially rotate relative to the shaft 14. An advantage of using the index-key 24b shown in
As illustrated in
In all of the previously described embodiments, the indexer 22 is secured or configured to be secured to the proximal end of the cannula 12. However, the indexer 22 can also be secured to other part(s) of the cannula 12. Referring now to
Referring specifically, to
As discussed previously, the number and location of the keyways 34 may vary. The number of key elements 25 of the index-key 24c may also vary. For example,
In the previously discussed examples, it is the indexer 22 that includes the keyways 34, and it is the index-key 24 that includes the key(s) 25. However, the indexer 22 is not limited to having keyways and the index-key 24 is not limited to having key elements, so long as the index-key 24 is capable of mating with the indexer 22. Referring now to
In particular, the probe assembly 70 includes an indexer 22d having one key element 71, and an index-key 24d having two keyways 72a and 72b. The key element 71 of the indexer 22d is preferably a projection, such as a pin, a peg, or a fin, that is secured to, or manufactured as a single unit with, an interior surface of the cannula 12. The index-key 24d has a tubular shape and an axis 27d, and is secured to the proximal end 18 of the shaft 14. Alternatively, the index-key 24d may be secured to the distal end 16 or anywhere along the shaft 14. The keyways 72 of the index-key 24d are located at an interior surface of the index-key 24d. The index-key 24d is configured to mate with the indexer 22d when the shaft 14 is advanced to deploy the wires 21a and 21b (
Although the illustrated embodiment of
In all the examples discussed previously, the index-key 24 is mated within the indexer 22. The indexer 22, however, can instead be mated within the index-key 24. Referring now to
In particular, the probe assembly 80 includes an indexer 22e having one key element 81, and an index-key 24e having two keyways 82a and 82b. The key element 81 of the indexer 22e is preferably a projection, such as a pin, a peg, or a fin, that is secured to, or manufactured as a single unit with, an exterior surface of the cannula 12. The index-key 24e has a tubular shape and an axis 27d, and is secured to the proximal end 18 of the shaft 14. The keyways 82 of the index-key 24e are located at an interior surface of the index-key 24e. The key element 81 of the indexer 22e is configured to fit within one of the keyways 82 of the index-key 24e when the index-key 24e is slid to fit around the indexer 22e.
The energy delivery probe 106 comprises an elongated tubular housing 128 having a distal end opening 116. Positioned within the housing 128 is an pusher 130. An array of flexible, flat wire electrodes 132 having tissue piercing ends is attached to a distal end of the pusher 130. The probe handle 120 is attached to a proximal end of the housing 128, and has a proximal end bore to allow a plunger 126 attached to the pusher 130 to be moved in and out of the handle 120. In particular, linear movement of the plunger 126 relative to the handle 120 causes a corresponding linear movement of the electrodes 132 relative to the housing 128 (and cannula 102), such that the electrodes 132 may be deployed out of the distal opening 116 of the housing 128. The index key 108 is located at the distal end of the handle 120 in order to mate with the indexer 110 at a relative position in which the electrodes 132 are completely positioned in the housing 128 when the plunger 126 is in its most proximal position relative to the handle 120, and completely deployed from the housing 128 when the plunger 126 is in its most proximal position relative to the handle 120. A cable 118 is electrically connected to the electrodes 132, in order to couple the electrodes 132 to a source of RF energy (not shown).
The sensing probe 406 comprises an elongated pusher member (e.g., a hypo-tube) 428 carrying a sensing element 405, such as a thermocouple for sensing temperature, or a transducer for sensing pressure, at a distal end 426 of the pusher member 428. The sensing probe handle 420 is coupled to a proximal end of the pusher member 428, the handle having a proximal end bore to allow a plunger 426 attached to the pusher member 428 to be moved in and out of the handle 420. In particular, linear movement of the plunger 426 relative to the handle 420 causes a corresponding linear movement of the pusher member 428 relative to the cannula 402, such that the distal end 426 of the probe 406 may be deployed out of the distal cannula opening 412. The index key 408 is located at the distal end of the handle 420 in order to mate with the indexer 410 at a relative position in which the sensor 405 is positioned in the cannula lumen 422 when the plunger 426 is in its most proximal position relative to the handle 420, and completely deployed from the cannula lumen 422 when the plunger 426 is in its most proximal position relative to the handle 420. A cable 418 is electrically connected to the sensor 405, in order to electrically couple the sensor to circuitry (not shown) for receiving the sensed data, e.g., corresponding to a tissue temperature or pressure.
By way of example, the sensing probe assembly 400 may be designed to measure the temperature at a selected tissue site, e.g., for monitoring tissue temperature in conjunction with a tissue ablation procedure. The cannula 402 is inserted into body tissue by conventional means thereby providing access for the sensing probe 406, which is inserted through the cannula lumen 422 and into the body tissue, with the indexer 410 mated with the index-key 408 in a first position. The temperature sensing element 405 is deployed from the distal cannula opening 412 into the tissue site by pushing the plunger 426 forward into the handle 420. Once the sensor 405 is in place (which may be detected through conventional ultrasound means), temperature data is obtained through the cable 418. The sensor 405 is then retracted from the tissue back into the cannula lumen 422 by pulling the plunger 426 proximally relative to the handle 420. The sensing probe 406 is then rotated relative to the introducer cannula 402, and the indexer 410 is mated with the index-key 408 in a second position, thereby providing access to a second tissue site at a fixed distance from the first tissue site for the temperature sensor 405. The process may be repeated by mating the indexer and the index-keys through further orientations (or by repeating prior orientations) of the probe 406 relative to the cannula 402, until the desired tissue temperature data has been obtained.
As discussed with respect to previously described embodiments, the energy delivery probe 106 and/or sensing probe 406 may alternately be provided with an index-key that includes an axial sleeve, as depicted in
Further, an indexer can also be secured or configured to be secured to the proximal end or within the lumen of the cannula 102/402 of the probe assemblies 100/400, as depicted previously in
Each of the indexers 22, 110, 410 described previously is secured to the cannula 12,102. It should be noted, however, that the indexer 22,110, 410 may also be secured to a patient or other object, such as an operation table or another medical instrument, as long as the indexer 22, 110, 410 is secured in a position relative to which the shaft 14 can move. For example,
The indexer 22, 110, 410 and the index-key 24, 108, 408 are not limited to those described previously, and may have other shapes and configurations, so long as the index-key 24, 108, 408 is capable of mating with the indexer 22, 110, 410 in a plurality of positions. For example, as shown in
It should also be noted that the operative element 20 is not limited to wires that delivery ablation energy. The operative element 20 can be a variety of instruments such as sensors, cutting devices, mapping instruments, embolic devices, or delivery devices. In addition, while depicted as wires, the operative element 20 can be any type of electrode. Although the indexer 22, 110, 410 and the index-key 24, 108, 408 were discussed previously with reference to a probe assembly or other medical devices, it is intended that the indexer 22, 110, 410 and the index-key 24, 108, 408 can also be fabricated separately from, for subsequent incorporation into, an existing medical device.
It should be noted that the configurations and shapes of the index-key and the indexer should not be limited to the examples discussed previously, and that the index-key and the indexer can have different configurations and/or shapes. For example, the index-key can be any structure or device configured to correspond with the indexer, which can also be any structure or device. In addition, instead of having the index-key coupled to a medical device, in other embodiments, the indexer could be coupled to the medical device. As such, the terms “index-key” and “indexer” should not be limited by the structure to which they are coupled to.
Thus, although several embodiments have been shown and described, it will be apparent to those skilled in the art that many modifications and changes may be made thereunto without the departing from the scope of the invention, which is defined by the following claims.
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